There is a lack of valid instruments for measuring productivity loss due to illness. This study aimed to compare the validities of traditional Chinese versions of the Work Productivity and Activity Impairment: General Health (C-WPAI:GH) and the World Health Organization's Health and Work Performance Questionnaire (C-WHO-HPQ), and to define the factors associated with productivity loss. We conducted a cross-sectional study of 165 Taiwanese employees in technology companies. Spearman's correlation coefficients and ANOVAs were used to test the validities of the C-WPAI:GH and C-WHO-HPQ. Bayesian model averaging was used for multiple linear regression to define the factors related to productivity loss. The C-WPAI:GH had acceptable validities for assessing the productivity loss of Taiwanese employees. The C-WHO-HPQ had acceptable content validity and concurrent criterion validity. However, the construct validity of the C-WHO-HPQ was insufficient (less than 75% of results were consistent with our hypotheses). Absenteeism in the C-WPAI:GH was associated with education, physical functioning and job satisfaction. There were significant associations of bodily pain, social functioning and general health with presenteeism, overall work impairment and activity impairment in the C-WPAI:GH. A linear correlation was found between education and activity impairment in the C-WPAI:GH. The C-WPAI:GH can be used to evaluate productivity loss due to illness.
Keywords: WHO-HPQ; WPAI:GH; occupational health; productivity; traditional Chinese; validity.